Wood Burning stoves: What You Need to Know
Using a Log Burner or Multi-Fuel Stove
By Liz Ransome-Croker
Article 6 of 6
Our guide to using a wood burning or multi-fuel stove takes you through how to light your stove, how to maintain it, how to use it efficiently.
Whether you’ve just bought a stove, are thinking of getting one, or have inherited one with a home you’ve moved into, there are a number of things to consider so you can make the most of your stove.
We’ve spoken to stove owners, installers and industry experts to get the best advice on using and maintaining your stove. Read on for everything you need to know - you can also watch our videos on the best way to light wood and coal on a stove.
If you're considering getting a stove, or want to find out whether you could save by using one, see our expert advice on stove costs and savings. This includes our stove costs tool to help you work out whether you'll save on your heating bill, as well as our handy downloadable checklist on buying, installing and using a stove.
Stoves: coal vs wood
There are clear benefits to burning wood, instead of coal. As well as coal being generally more expensive than wood, it produces much more CO2, so is less environmentally friendly.
A wood burning stove can only burn wood, whereas a multi-fuel stove can also burn coal. To help you decide which to buy, we spoke to owners* of both types of stove.
We asked them whether they believe their stove has saved them money on their energy bills. More people with a wood burning stove believe it has:
- Wood burning stoves - 46% of owners said it saved them money.
- Multi-fuel stoves - 39% said it saved them money.
If you're thinking of getting a multi-fuel stove, think about what fuel you're going to use. According to a survey conducted by the Stove Industry Alliance (SIA), 77% of multi-fuel stoves owners said they used their stove exclusively to burn wood.
As not all multi-fuel stoves burn wood as efficiently as dedicated wood burning stoves, those people would be better off with a log burner.
For more information on different types of stoves and to find out which is right for you, see our guide to types of stoves.
Sourcing wood for your wood burning stove
To make sure you get the most out of your wood burning stove, it’s important to use the right kind of wood.
First and foremost, it's important that you burn as dry wood as possible - ideally it should only contain less than 20% moisture.
Only burn wood with 20% or less moisture.
Using fresh logs with a high moisture content of around 60% to 90% will reduce your stove’s heat output.
This is because you’ll waste energy burning off the water, so you’ll need to use more to warm the room. It will also leave more build-up in your chimney, create more smoke and potentially harmful air pollution.
Never burn freshly-cut wood as it creates a lot of smoke and makes the stove dirty
You can reduce the moisture content of freshly cut wood by drying it yourself, which is called seasoning. To do this, it’s best to store the wood in a dry place for at least a year, preferably two. To help you work out how dry your wood is, you can also buy a moisture meter - these cost around £20.
For the best results, the wood should be left on a dry surface protected from rain. Leave the sides exposed to air and wind, as it will speed up the drying process. You can buy dedicated wood stores to help with this.
Chopping the wood down to size before storing it will also help it to dry more quickly. Alternatively, you could buy ready-seasoned wood at a little extra cost - see more about fuel prices below.
When we asked stove owners about the types of fuel they use, the highest proportion (69%) use seasoned logs, while the second largest (14%) use kiln-dried logs. 13% also said they collect free wood, from their garden, a neighbours or in local wood.
Different types of logs will state the estimated heat output when it's burnt in kWh - the higher this is, the more heat it will produce.
It's also worth looking out for the Ready to Burn logo, as this means the wood has 20% or less moister and is from an approved supplier.
Launched by wood-assurance organisation Woodsure, the government-backed scheme means wood manufacturers must meet certain criteria to use the label. Their wood is also tested and verified by Woodsure.
Cost of wood fuel
The price of wood varies, depending on where you are in the country and what type of wood you buy. Wood is often sold in large bags by the cubic metre, or in smaller bags and nets in kg. It's sometimes also sold by the pallet.
To give you a rough idea of the cost of different types of fuels, we've looked at the prices listed on five log-supplier websites. All sites deliver across the UK, and the prices for seasoned and kiln-dried logs don't include delivery, but the price for the wood pellets and briquettes do.
- Ready-seasoned wood has around 25% to 40% moisture content, depending how long and how well it has been dried out. It can usually be purchased for around £125 per cubic metre. Burning wood that has been seasoned will give you a heat output of about 3kWh per kg.
- Kiln-dried wood is more expensive, about £140 per cubic metre, but it's more efficient and can be used immediately. On average, it contains less than 20% moisture, and burning it produces a heat output of around 4.5kWh per kg.
- Briquettes, fuel created from crushing recycled wood or paper, have a low moisture content - as little as 10% or less, so they burn very efficiently and have a heat output of around 5kWh. These are sold by the kg, and usually cost around £242 for 1,000kg.
- If you have a specialised wood-pellet stove, you can usually buy wood pellets online or from a local supplier. Wood pellets are sold by the kg and cost around £290 per 1,000kg. The Stove Industry Alliance (SIA) recommends that you buy ENplus standard pellets, which have roughly 10% moisture content and will give you a heat output of around 5kWh per kg.
The prices for the logs are for hardwoods, such as ash, beech, birch and oak. It's also preferable to burn hardwoods, instead of softwoods, such as pine or fir. Hardwoods do cost a little more, but take longer to burn, so you'll use less.
Note that 500kg equates to around one cubic metre, so working out how much wood will cost for the amount you'll use is a little tricky. But you can find out more about how to calculate this, as well as the costs of buying, installing and using a stove, in our expert guide to stove costs and savings.
Kindling can be sourced from pallets used for building suppliers and found in skips (just check with the owners first)
It is sometimes possible to collect wood fuel free of charge from building sites, skips or local woods - a number of stove owners we asked do this.
But legally you don’t have a right to it, so it’s really important to check first with the site or land owners that they’re happy for you to take it. It’s worth also asking whether the wood has been treated with chemicals - if it has, it could be unsafe to burn.
A lot of stove owners also said that they use wood from their own gardens, or that of friends and family, to burn on their stove, so it's free. But, as mentioned, it must be dried out as much as possible first.
How much wood will I need?
As a rough guide, an average-sized house that uses a stove in the evenings and at weekends will need about three to four cubic metres of wood a year.
Although wood itself is considered a carbon-neutral fuel, transporting it uses CO2. So it’s best to try and find a supplier close to home. You can find a local supplier on the wood-fuel directory website.
Cost of coal for your multi-fuel stove
There are a number of different types of coal, all made in different ways. But there are two main types of coal that are used on a stove: house coal and smokeless coal.
House coal is more expensive and less environmentally friendly, as it produces more emissions than smokeless coal. It also creates more ash and therefore will mean your stove requires a little more maintenance.
Smokeless coal is an umbrella term for a few different types of coals that produce less smoke as they burn. It includes anthracite coal, which occurs naturally, but can also be manufactured.
Coal is generally sold in 10kg bags, but you can buy in bulk to reduce costs. It has a heat output of around 8kWh per kg.
Roughly speaking, a 10kg bag of house coal can cost between £5 and £10, while smokeless coal costs around £10 to £15.
Videos: lighting a stove
Everyone's home and stove are different, so a lot of different factors - such as air pressure, the type of flue you have, etc - can change the way you light and use your stove.
Finding the most effective way to ignite your stove and keep it burning at the right temperature will take a bit of practice. But our videos and step-by-step tips will help you get started.
Lighting and controlling your wood burning stove
7 steps for lighting and controlling your wood burning stove
1. Fully open the air vents. There will be a primary vent at the bottom and, if you have one, a secondary vent (also called an airwash) at the top.
2. Create a base for the fire. Place a firelighter or, to be more eco-friendly, paper or beeswax, together with some dry kindling wood and scrunched-up paper on the grate. The flue needs to get hot. Make a tepee shape with the wood and paper to help direct the heat up so it warms quicker.
3. Light the firelighter or paper/beeswax and leave the door slightly ajar. This will help the heat travel up the flue and minimise condensation on the glass.
4. Once the fire is going, add some larger pieces of wood. Be careful not to add too many logs, as they could smother the fire.
5. When the logs have caught, and the fire is fully established, close the door completely and shut the vent at the bottom of the stove. You can use the secondary vent to control how the fire burns - opening it increases the heat output and should help a dying fire re-establish.
6. Add more logs once the current ones have burnt down, but are still glowing red. Using a poker, spread the embers evenly. Then place more logs on top, leaving space for air to circulate.
7. Close the door and open the vents until the logs are burning well. Once they are, close the primary vent and use the secondary one in the same way as before.
Lighting and controlling your multi-fuel stove
8 steps for lighting and controlling your multi-fuel stove
1. Half close the top air vent and open the bottom one. This allows air to circulate under the coal.
2. Create a base for the fire with a firelighter (eco versions are available) and scrunched-up paper. On top of this, add dry kindling wood. The flue needs to get hot. Make a tepee shape with the paper and kindling to help direct the heat up the flue.
3. Light the firelighter or paper, leaving the door slightly ajar. This will help the heat travel up the flue and minimise condensation on the glass.
4. Once the kindling has burnt down to glowing embers, add the coal.
5. Once the fire has established, close the door and the vent at the top of the stove, if you have one.
6. You can use the primary air vent at the bottom to control how the fire burns. Opening it increases the heat output and should help a dying fire re-establish.
7. When you want to add more coal, first clear ash from the grate using the stove’s riddling mechanism or a poker.
8. Add the coal, close the door and open the primary air vent again until the coal is burning well. Once it is, you can use this vent in the same way as before.
When burning coal and wood, it's key to make sure the flue heats up and stays warm. This will help avoid carbon monoxide coming down the chimney and creosotes building up, which can be flammable. Make sure you have left enough time for the flue to heat up before adding logs or coal - the fire should be burning well, but not fiercely.
It's worth buying a stove thermometer to monitor the temperature - this will go on the side of the stove. Most stoves should stay between 200 and 250°C, but this can vary for each stove, so check with the manufacturer.
Thanks to Pinkerbell Stoves for allowing us to film these videos in its store.
Pollution from stoves
There has been a lot in the media recently about potentially harmful pollutants from stoves. Pollutants are generated from a range of things we encounter in our daily lives - from cars on busy streets, to cooking and vacuuming in our homes.
Combustion - created by wood and coal fires, but also by burning candles and gas cooking - produces tiny particulate matter. This can also come from dusting and vacuuming. Particulate matter can inflame your airways and increase the risk of lung and heart disease if inhaled at persistently high levels over time.
Poor ventilation can exacerbate any issues. While energy-saving measures, such as double-glazing and insulation, are laudable, they can mean our homes aren't being aired. This results in potentially harmful emissions not being expelled as much as they should be.
If you're concerned about pollutants, we would suggest doing the following:
- Only burn untreated, fully dried wood. Ensure the flue stays at the right temperature throughout use. Clean the flue and chimney regularly so smoke can escape efficiently.
- Vacuum regularly to control airborne particles, preferably with a vac that sucks up dust with minimum emissions back into the air. Consider a HEPA filter if you have allergies.
- Use extractor fans or cooker hoods, and open the windows or any trickle vents.
You might want to also consider an air purifier. Our tests reveal the ones that can be trusted to quickly and effectively clean the air in your home - find out which are the best air purifiers.
Air pollution in the home
In December 2016, we took snapshot measurements of air-quality and ventilation rates in three semi-detached houses:
- ‘Draughty’ Victorian
- 1950s house with many insulating improvements
- New-build end-of-terrace.
Our measurements were taken with the windows closed before, and almost immediately after, concentrated bursts of common household activities, including vacuuming, cleaning, cooking and using personal care and scented products.
We discovered surprisingly high levels of pollutants with potential cumulative long-term health effects in all of our test houses.
While the activities we performed were relatively short-term – making a fry-up, cleaning the bath and vacuuming – it’s the prolonged exposure to the generated pollutants that could cause health problems. These problems are likely to be more noticeable in individuals with pre-existing respiratory conditions.
Which? members can read our full report on air pollution to find out more about the potential risks and how to minimise any issues.
If you're not a Which? member, you can sign up for a £1 trial subscription to gain instant access to this entire expert guide, including our stoves cost calculation and handy downloadable PDF checklist, and all our reviews.
Stove maintenance and safety
If you choose the right stove, it should be fairly easy to maintain. But there are a few steps you should take to keep it efficient and safe.
To keep your stove in good working order, the Stove Industry Alliance recommends that you have your chimney swept at the beginning and the end of the winter to avoid a build-up of tar and soot, which could damage the chimney and stove when not in use.
From a safety point of view, blocked chimneys can also cause deadly carbon monoxide. One sweep should cost £30-£60.
It's also worth getting a carbon monoxide alarm to alert you to the presence of the dangerous gas in your home. Unfortunately, our rigorous tests have found models that won't protect you - see which are the best carbon monoxide monitors.
Wet or unseasoned logs will leave more sooty deposits and could increase the number of sweeps you need, so it’s best to use seasoned or kiln-dried wood to cut down on maintenance. You can find a chimney sweep in your area by visiting The National Association of Chimney Sweeps website.
If you have a pellet stove, you will also need to have a yearly service, as the stove has electrical working parts. This can cost around £200.
It’s also a good idea to clean out the ash from the ash pan and to clean the glass regularly. Keep in mind, though, that leaving a layer of ash can help to start a wood fire and keep it burning. So it's best to check the manufacturer's guide for specific instructions on how often to clean it out.
If your stove has airwash - a cool-air vent that helps to stop tar building up on the glass - you may not need to clean the ash or glass as often.
Some stoves also have special cleanburn or cleanheat technologies, which pull in extra air to help burn off more smoke, reducing sooty deposits.
Use damp newspaper dipped in ash to clean the glass, then reuse the newspaper as kindling for your next fire
When cleaning out the stove, it’s worth keeping an eye out for any cracks, distortions, breaks in the seals, holes or rust. These can all affect the stove’s performance and safety.
Depending on how long you’ve had the stove, getting the affected part repaired or replaced if there are any problems may be covered in the manufacturer’s warranty. For more information on stove warranties, see our guide to installing a stove.
If you have children or pets, you might want to consider getting a fireguard to go around the stove. Also, it's worth having a bird guard fitted at the top of the chimney to stop birds nesting - this shouldn’t add a lot to the installation costs.
We recommend getting a carbon monoxide detector to sit in the room where the stove will be - it's a legal requirement with stoves installed after 2010 and for stoves in rented properties. This must be placed on the ceiling at least 30cm away from any wall or, if it is located on a wall, as high up as possible (above any doors and windows) but not within 15cm of the ceiling. It must also be located between 1m and 3m horizontally from the stove.
Carbon monoxide detectors only cost around £15 and monitor whether any carbon monoxide, which is tasteless and odourless and highly poisonous, is being expelled.
It’s also worth installing a smoke alarm in the room where the stove will be fitted. Take a look at our smoke alarm reviews to find the best - we found two you should avoid because they failed our safety tests.
(*August 2017 survey of 237 stove owners and Which? members who have a stove as well as central heating.)